Optimisation of the microwave-assisted extraction of natural antioxidants from defatted black rice bran of oryza sativa L. CV. homnin

Abstract

This research aimed to improve antioxidant extraction of Hom Nin rice bran using microwave-assisted extraction by Response Surface Methodology. The results showed that the predicted values i.e. total phenolic content, total flavonoids, anthocyanin and antioxidant activities (DPPH), were close to the predicted results which were 89.89 mg GAE/g DM, 76.98 mg CE/g DM, 18.08 mg C3G/g DM and 107.72 μmol TE/g DM, respectively. Comparing with the results obtained from the optimum extraction condition which the three factors were used as followings: 648 watt of power energy, 0.076 mol/dm3 of citric acid concentration and 83 second of extraction time, the experimental values were 90.59 mg GAE/g DM, 77.53 mg CE/g DM, 18.82 mg C3G/g DM), 109.35 μmol TE/g DM, respectively.